The present invention relates to a relief valve used in combination with suction-operated automatic swimming pool cleaners. Suction-operated automatic swimming pool cleaners typically operate by connecting a long flexible hose between the cleaner and the water inlet of the swimming pool skimmer or weir. The skimmer or weir contains the inlet to the swimming pool filter system. The flexible hose used to connect the swimming pool cleaner generally is made up of several sections connected together by friction couplings. Water is drawn through the pool cleaner and the flexible hose by the filter pump. The suction produced by the filter pump is used by the pool cleaner as a motive force to randomly move the pool cleaner about the horizontal and vertical surfaces of the pool and to help hold the pool cleaner against the sides of the pool being cleaned, as well as drawing dirt and debris into the pool filter.
Suction-operated pool cleaners require a relatively steady, even flow of water for proper operation. Excessive flow causes the pool cleaner to adhere firmly to the pool in one position and not randomly move about all the pool surfaces. In addition the kinetic energy released by water moving within the flexible hose when the filter pump suddenly shuts off has a tendency to separate the flexible hose at its couplings, disabling the pool cleaner (an unacceptable result for a device which is designed to be totally automatic and require no attention from the pool owner). Therefore, it is important that suction-operated pool cleaners be supplied with a steady, even flow of water.
One problem with prior art relief valves is that when the swimming pool cleaner is connected to the pool skimmer or weir, the inlet to the skimmer or weir is plugged, and debris floating on the surface of the pool is not drawn through the pool filter and instead collects on the pool strainer. This accumulation of debris on the strainer must be removed manually by the pool owner, a dirty task that detracts from the otherwise enjoyable aspects of pool ownership. Accordingly, it is desirable to provide some means of allowing floating debris to be drawn into the pool filter system simultaneously with the operation of the automatic pool cleaner.